/Engine/Plugins/Online/OnlineSubsystem/Source/Public/Interfaces/OnlineSessionInterface.h
virtual [FDelegateHandle](API\Runtime\Core\Delegates\FDelegateHandle) AddOnCancelMatchmakingCompleteDelegate_Handle ( const [FOnCancelMatchmakingCompleteDelegate](API\Plugins\OnlineSubsystem\Interfaces\FOnCancelMatchmakingCompleteDele-) & Delegate )